The present invention relates to novel biologically active vitamin D.sub.3 analogues which include at least one hydroxyalkyl substituent in the 1-position. More specifically, the present invention relates to a compound YB which is a vitamin D.sub.3 analogue which includes a hydroxyalkyl substituent in the 1-position and a modified D-ring side chain. Compound YB is a potent anti-proliferative vitamin D.sub.3 analogue but has a very low (.about.10.sup.-3 relative to calcitriol) binding affinity to the calf thymus vitamin D.sub.3 receptor (VDR).